Numerous attempts have been made to formulate laundry detergent compositions which provide the good cleaning performance expected of them and which also have good through-the-wash fabric conditioning benefits, such as softening and antistatic properties. Attempts have been made to incorporate cationic conditioners in anionic surfactant-based built detergent compositions employing various means of overcoming the natural antagonism between the anionic and cationic surfactants. For instance, U.S. Pat. No. 3,936,537, Baskerville et al., issued Feb. 3, 1976, discloses detergent compositions comprising organic surfactant, builders, and, in particulate form (10 to 500 microns), a quaternary ammonium softener combined with a poorly water-soluble dispersion inhibitor which inhibits premature dispersion of the cationic in the wash liquor. Even in these compositions some compromise between cleaning and softening effectiveness has to be accepted. Another approach to provide detergent compositions with softening ability has been to employ nonionic surfactants (instead of anionic surfactants) with cationic softeners. Compositions of this type have been described in, for example, German Pat. No. 1,220,956, assigned to Henkel, issued Apr. 4, 1964; and in U.S. Pat. No. 3,607,763, Salmen et al., issued Sept. 21, 1971. However, the detergency benefits of nonionic surfactants are inferior to those of anionic surfactants, especially relative to alkyl sulfates and alkyl ethoxylated sulfates, which provide excellent cleaning performance in liquid detergent compositions.
In European Patent Application No. 87202159.7, filed Nov. 6, 1987, amine-anionic compound ion-pair complex particles having an average particle diameter of from about 10 microns to about 300 microns were disclosed. These particles provide excellent through-the-wash conditioning without significantly impairing cleaning performance. European Patent Application No. 87202159.7 further discloses that ion-pair particles which are made from lower alkyl chain length linear alkyl benzene sulfonates impart improved processing characteristics and also improved chemical stability in liquid detergents to provide longer shelf-life to the conditioning agent particles. Even further improvements in the processing characteristics and chemical stability of amine-organic anion ion-pair complex particles are obtained by incorporating certain levels of amine-inorganic ion-pair complexes into the particles as disclosed in U.S. patent application Ser. No. 153,172, "Conditioning Agent Containing Amine Ion-Pair Complexes and Compositions Thereof" filed by Debra Caswell on 2-8-88, cofiled with the present U.S. patent application. Still, further improvements in stability of the ion-pair particles in liquid detergent compositions that are aggressive toward ion-pair conditioning particles, such as compositions containing high levels of anionic and nonionic surfactants, fatty builders, and polar solvents, are desirable. Also, higher levels of cleaning performance in conjunction with excellent through-the-wash fabric conditioning are desirable.
It is an object of this invention to provide a liquid detergent composition having excellent cleaning performance and excellent through-the-wash fabric conditioning performance. More specifically, it is an object of this invention to provide a liquid detergent composition as described above wherein the fabric conditioning agent therein comprises amine-organic anion ion-pair complex particles, and wherein the conditioning particles have improved stability, and therefore extended shelf-life, in detergent compositions with exceptional cleaning performance.